1. Field of the Invention
This invention relates generally to glazing units and, in one particular embodiment, to an architectural or vehicle transparency having improved solar control performance.
2. Technical Considerations
Vehicle transparencies, such as but not limited to vehicle windows, windshields, rear lights, sunroofs and moonroofs, are designed to allow light to enter the vehicle and also to allow the vehicle occupants to see out of the vehicle. However, one drawback of these vehicle transparencies is that they not only allow light to enter the vehicle but also allow heat to enter the vehicle as well. On warm, sunny days, the vehicle operator may choose to increase the air conditioning of the vehicle to counteract the heat load introduced through the transparencies. This wastes energy and increases fuel consumption.
One solution to this problem has been to use colored or tinted glass to reduce the heat transfer through the transparency. While this does provide some relief, this solution also has some disadvantages. For example, using colored or tinted glass cuts down on the visibility through the transparency. Also, the colored glass absorbs heat more readily than clear glass and can become hot to the touch. Another solution has been to provide solar control coatings on the vehicle transparencies. However, conventional solar control coatings can be expensive to apply and also can limit visibility through the transparencies. This is particularly relevant for vehicle windshields and front windows due to the requirement to meet government imposed limits on minimum visible light transmission through such transparencies.
Therefore, it would be desirable to provide a vehicle that reduces or eliminates at least some of the problems associated with conventional vehicle transparencies.